1. Field of the Invention
The surface treated material of the present invention is excellent in adhesion for painting layer, corrosion resistance after painting and press formability and it can be used in a wide range of application uses such as for automobiles, home electric appliances and building materials.
2. Description of the Prior Art
Metal materials represented by steel sheets are often used after applying plating with an aim of improvement for corrosion resistance, esthetic nature or the like. However, requirement for the properties or performances of platings such as corrosion resistance has been increased more and more along with a further development of technology and counter-measures has been carried out, therefor include, for example, (1) increase of deposition amount of plating, (2) use of Zn series alloys plating such as of Zn-Ni or Zn-Fe.
Further, in the application use as described above, painting is generally applied before use and it is also necessary to provide good adhesion for painting layer. However, since no sufficient adhesion for painted layer can be obtained in Zn or Fe series platings, a pre-treatment has been conducted by using phosphate, chromate or the like.
However, in the methods (1) and (2) above, so-called flaking or powdering is caused in which plating layers are peeled off upon press forming to result in troubles. Further, the pre-treatment for the painting makes the step complicate to increase the cost.
For overcoming the foregoing problems, dispersion of an organic or inorganic compound to the surface layer of the substrate or in the plating layer has been conducted (for example, in Japanese Patent Laid-Open Sho 61-127887, 61-264200 and Japanese Patent Publication Hei 1-36559), to obtain a considerably satisfactory result but no sufficient adhesion for painting layer and corrosion resistance after painting have yet been obtained.
The present invention has been accomplished in view of the foregoing situations and it is an object thereof to provide a surface treated material less suffering from degradation after painting and excellent in adhesion for painting layer, corrosion resistance after painting and press formability.